how can i select 2 markers using python?
Can do this without the operators

import bpy
from bpy import context

scene = context.scene

start_marker = scene.timeline_markers.new("start") # make a new marker
start_marker.frame = scene.frame_start # set a frame
start_marker.select = True # set selected
end_marker = scene.timeline_markers.new("end")
end_marker.frame = scene.frame_end
end_marker.select = True

# get a marker
marker = scene.timeline_markers.get("start")
if marker:
    print(marker.name, marker.frame, marker.select)